<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <div id="app">
        <input type="button" value="修改" @click="set">
        <input type="text" name="" id="" v-model="msg" @keyup.enter="get">
        <h2>{{msg}}</h2>
    </div>
    <script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
    <script>
        var app = new Vue({
            el: "#app",
            data: {
                msg: "aa"
            },
            methods: {
                get() {
                    alert(this.msg);
                },
                set() {
                    this.msg = "hh"
                }
            }
        })
    </script>
</body>

</html>